Long- Stator Comprising A Ground Conductor And Maglev Railway That Is Equipped With Said Stator

ABSTRACT

A long-stator and a magnetic levitation railway equipped therewith are described. The long-stator comprises a plurality of stator sections ( 1, 1   b ) that are arranged one behind the other, adjoin one another at separation points ( 22 ) and have grooves ( 2 ) following each other in a longitudinal direction for receiving at least one alternating current winding ( 4 ) and at least one ground conductor ( 17 ) extending in longitudinal direction for grounding said alternating current winding ( 4 ). According to the invention the ground conductor ( 17 ) comprises, at least in the vicinity of critical separation points ( 22 ), a conductor section ( 25 ) that bridges the separation point ( 22 ) and is configured as a loop ( 24 ) (FIG.  10 ).

The invention relates to a long stator of the species indicated in the preamble of claim 1 and to a magnetic levitation railway (Maglev Railway) according to the generic term of claim 21.

With magnetic levitation railways having long-stator linear motors, a long-stator is provided alongside a guideway, into the grooves of which a three-phase alternate current winding is inserted, which for example consists of a copper or aluminum cable and an insulating layer surrounding it. Since difference in voltage occur due to inductive effects in normal operation along the windings and because currents thereby caused may flow, it is known (DE 30 06 382 C2) to provide the windings with an additional outer sheath made of an electrically isolating plastic material, being made at least partly electrically conductive with carbon black, graphite, a copper mesh or otherwise in order to discharge these and other electric currents, to ensure hazard protection on contact and for other reasons, and to connect this sheath in the area of each groove to a ground conductor extending alongside the long-stator. To ensure that small transitional resistances are obtained between the sheath and the ground conductor, it is furthermore well known practice (DE 196 20 222 C1) to connect the winding sheath to the ground conductor by means of devices which consist of sleeves partly surrounding the windings, are inserted into the grooves of the long-stator and comprise connecting elements for the ground conductor. Thereby it is intended on the one hand to establish a comparably large contact between the sheath and the sleeves, while the connecting elements on the other hand are intended to allow for a simple connection to the ground conductor. For avoidance of corrosion, the sleeves and the connecting elements are made of stainless steel.

The ground conductors hitherto known consist of a well conducting material, e.g. copper. They are connected at optional points and optionally frequently to the ground potential and provided with a conductive plastic sheath like the alternating current windings to provide corrosion and contact protection.

In practical use of magnetic levitation railways, two essential weak points have shown up in the described devices. On the one hand it was found out that the plastic sheath of the ground conductor was scorched through at numerous points after a longer period of operation. Such scorched points indicating thermal overloads are not tolerable. On the other hand, fire and/or carbonization points also occur in the sheath of the long-stator winding itself, whereby the sheath gradually becomes brittle and begins to dissolve. This is not tolerable either.

To avoid these two weak points, it was proposed in a non-published German patent application 10 2004 015 096.6 filed by the same applicant to produce the ground conductor exclusively from a non-corrosive metal, e.g. from stainless steel. Thereby it is intended to prevent that undesirably high transition resistances and, consequently, thermal peak loads may occur due to the small transition cross-sections of the connecting elements when electrical currents are transferred from the sleeves to the ground conductors which peak loads exceed the thermal load-bearing capacity of the plastic insulation of the ground conductors and therefore cause scorching wherever they are the greatest.

However, by applying ground conductors made of stainless steel or the like and distinguished by a high tensile strength, another problem arises. A long-stator of the described kind is composed of a plurality of stator portions which are arranged one behind the other in the longitudinal direction of a guideway for a magnetic levitation railway and which abut each other at separation points (joints). The distances of these stator portions must be able to vary by some millimeters at certain joints, e.g. those lying in the area of switches, due to movements of the switches. A tensile-proof ground conductor cannot follow these changes, all the more so because these changes may add up to far greater values if contemplated e.g. over the length of a switch. Therefore, forces are exerted through the ground conductor onto the connecting elements which may plastically deform and thereby reduce the clamping effect and thus also the size of the contact areas between the sleeves and the ground conductor. This may ultimately lead to a failure of a contact between a sleeve and the ground conductor which is even speeded-up by oscillations and vibrations occurring during operation. Even a rupture of the ground conductor cannot be precluded. Corresponding problems may occur in the area of other separation points (joints) like the joints in the area of switches, hereinafter briefly designated as “critical” separation points.

Starting thereform it is the object of the present invention to configure the long-stator of the species designated hereinabove in such a manner that necessary changes in distance between adjacent stator portions cannot lead to a failure of electrical contacts between the sleeves and the ground conductor. Moreover, it is intended to propose a magnetic levitation railway which is equipped with such a long-stator.

The characterizing features of claims 1 and 21 serve to solve this object.

The present invention bears the advantage that a ground conductor reserve is established in the area of the critical separation points by way of a loop in the ground conductor that may—in case of changes in distance between long-stator portions—supply and take-up those material quantities portions which are required to make possible these changes in distance, without this causing any tensile stress for the actual ground conductor or any excessive load for the connecting elements or the like.

Other advantageous features of the present invention become evident from the subclaims.

Giving some embodiments, the present invention is explained in more detail based upon drawings attached hereto, wherein:

FIG. 1 schematically shows a perspective view of the long-stator of a linear motor with a three-phase alternating current winding for a magnetic levitation railway;

FIG. 2 shows a front view of the long-stator according to FIG. 1 in the area of a groove during insertion of the winding;

FIG. 3 shows a perspective view of the winding according to FIG. 1 without a long-stator after insertion into the sleeve according to the present invention together with a ground conductor;

FIG. 4 shows a partial and a schematic side view of a long-stator in the area of a switch and with a first embodiment of the device according to the present invention in the switch area;

FIG. 5 and FIG. 6 each show an enlarged front and side view of a clamping connector of the device according to FIG. 4.

FIG. 7 shows a side view according to FIG. 4 of a second embodiment of the present invention;

FIG. 8 shows a perspective view of a clamp of the embodiment according to FIG. 7;

FIG. 9 shows a side view according to FIG. 3 of a third embodiment of the present invention;

FIG. 10 shows a perspective front view of the embodiment of FIG. 9;

FIG. 11 to FIG. 16 in a front view, bottom view, top view, rear view, side view, and perspective view each show a mounting means of the embodiment according to FIG. 9 and FIG. 10;

FIG. 17 in an enlarged perspective view shows details of the mounting means according to FIG. 11 to FIG. 16 in a partly pre-assembled status;

FIG. 18 shows a perspective view according to FIG. 10 of a fourth embodiment of the present invention;

FIG. 19 shows a metal sheet blank for production of the mounting means according to FIG. 11 to FIG. 16;

FIG. 20 and FIG. 21 show perspective views of the mounting means according to FIG. 11 to FIG. 16 at various stages during production, and

FIG. 22 to FIG. 27 show front views and perspective views of two counter-pieces after their separation from the mounting means according to FIG. 20.

FIG. 1 shows a portion of a long-stator 1 of a linear motor for a magnetic levitation railway. Within preselected distances, the long-stator 1 has grooves 2 which are continuously configured in a direction transverse to its longitudinal axis 3 in order to accommodate a three-phase alternating current winding 4. For example, a reaction part of a magnetic levitation vehicle provided with a carrying magnet is guided at the underside of the long-stator 1 in the direction of the longitudinal axis 3. The general set-up and the mode of operation of such a long-stator linear motor are widely known to those skilled in the art, e.g. from the printed publication DE 39 17 058 C1, which for the sake of avoiding repetitions is hereby made an integral part of the present disclosure.

According to FIG. 2, the grooves 2 each are opened outwardly and/or downwardly through slots 5 and confined by walls 6 which have inwardly protruding projections 6 a that stand opposite to each other and which have distances to each other at a narrowest points that are smaller than corresponds to the outer diameter of the winding 4.

As is furthermore shown on FIG. 2 the parts of wall 6 lying on both sides of the grooves 2 are provided with a support shoulder 7 each near the opening slot 5. Two lower longitudinal edges 8 of a sleeve 9 are supported on these support shoulders 7, said sleeve being comprised of a thin stainless steel metal sheet shaped according to wall 6. The sleeve 9 is preferably resilient to allow it to be pressed in the direction of an arrow shown in FIG. 2 into the groove 2 until its longitudinal edges 8 snap into place behind the support shoulders 7. Thereby, the sleeve 9 is then fixed in groove 2 in a non-turnable status and secured to prevent it from falling-out.

At those places where the walls 6 have their projections 6 a, the sleeve 9 is shaped accordingly so that the groove 2 has a constriction 10 after the sleeve 9 has been inserted.

Since the windings 4 can be slightly deformed elastically, they can also be pressed into the grooves 2 in the direction of the drawn-in arrow after the sleeves 9 have been inserted until they elastically snap into place behind the constrictions 10 and are thereby secured against falling-out.

The configuration of the grooves 2 and sleeves 9 are widely known to those skilled in the art, e.g. from the printed publication De 196 20 222 C1, which for the sake of avoiding repetitions is hereby made an integral part of the present disclosure.

Further details of the sleeve 11 become evident particularly from FIG. 3. Accordingly, the sleeve 11 receives a shell 12 having a contour which mainly follows the contour of a cylindrical surface and which is so large that it encircles the winding 4 in a mounted condition by a bit more than a half. The length of the shell 12 in the direction of its longitudinal axis mainly corresponds to the length of groove 2 so that it fills it completely on its entire length after insertion. At one axial end, the sleeve 9 has a stop in form of a connection lug 15 to which a connecting element 16 for a ground conductor 17 is fastened. The connecting element 16 is preferably comprised of a spring channel into which the ground conductor 17 can be pressed elastically and thereby undetachably fixed.

The usual set-up of the winding 4 becomes evident from FIG. 3. Accordingly, the winding 4 comprises a multi-stranded, electrically good conducting core 19, a high-voltage insulating layer 20 surrounding it, and an outer sheath 21 wrapped around said layer 20 and made of a plastic material that has been made at least partially conductive, e.g. with carbon black or the like. Accordingly, both the insulating layer 20 and the sheath 21 are elastically resilient and/or can be compressed within certain limits.

Finally, from FIG. 3, it becomes evident that every straight winding strand of windings 4 lying between the winding heads is provided with a sleeve 11 inserted into a groove 2 not shown here. Having inserted the sleeves 11, the connecting elements and/or spring channels 16 lie coaxially one behind the other in order to jointly take-up the ground conductor 17 extending in the longitudinal direction of the guideway.

The sleeve 11 is entirely made of a stainless steel metal sheet, to which the component parts 15 and 16 are moulded to, e.g. after a punching step by applying usual shaping steps.

According to FIG. 3, the connecting element 16 takes-up the ground conductor 17. To ensure that good contacts with little transition resistances are obtained here, too, the connection lugs 15 and spring channels 16 are of a large-area configuration. In particular, this applies with respect to the smaller flow cross-sections of these parts in comparison with the sleeve 11. Moreover, the present invention provides for producing the ground conductor 17 exclusively from a corrosion-resistant metal. Thereby, the problems occurring if hitherto usual insulating layers are used, are avoided which problems occur in the area of sharp-edged contact points. Furthermore, the ground conductor 17 is advantageously made of the same material as the sleeve 11, i.e. from stainless steel, in order to preclude even those interferences like for instance contact corrosion that might occur in the area of the contact points due to the electrochemical contact series, if unfavourable metal combinations are used, e.g. Cu/Fe. Moreover it bears the advantage that stainless steel is corrosion-resistant so that an additional corrosion-protection layer is not required. Instead of stainless steel, however, other corrosion-resistant materials, e.g. tin-coated copper, titanium or the like could also be used. Finally another advantage is that the current carrying capacity between the connecting element 16 and the ground conductor 17 is substantially greater due to the lack of an insulating layer.

Besides, the ground conductor 17 is expediently made of a stainless steel rope, even if it could also be configured as a massive rod or otherwise.

As is particularly shown on FIG. 4, the long-stator 1 is usually composed of a plurality of stator portions 1 a, 1 b arranged one behind the other in the direction of its longitudinal axis 2 and adjoining at separation points 22. At critical joints or separation points 22, respectively, e.g. at those lying in the area of switches of a not precisely shown guideway for a magnetic levitation railway, it might be required that the ends of the stator portions 1 a, 1 b adjacent to the separation point 22 can execute relative movements by some millimeters. The inflexible stainless steel rope 17 usually does not permit such movements.

According to the present invention it is therefore provided to separate (divide) the ground conductor 17 in the area of critical separation points between long-stator portions 1 a, 1 b and to protect the ends thus obtained from splicing-up by security means 23 of any kind. For example, tubular end pieces 23 drawn onto the obtained ends and then squeezed are suitable for this purpose. The ends of the ground conductor 17 thus obtained are electrically connected to each other, for example by a slightly bent conductor section 25 provided with a loop 24 or configured as a loop and preferably made of the same material as the ground conductor, wherein the ends of said conductor section 25 lying on both sides of the separation point 22 are connected by the aid of clamping connectors 26 to the two cut ends of the ground conductor 17. Accordingly, the loop 24 constitutes an elastic reserve portion of the ground conductor which bridges the separation point 20 like an arched bridge and which may supply or take-up the material quantities required in case of changes in the distance of the long-stator portions 1 a, 1 b, without this causing any tensile stress for the actual ground conductor 17 or any excessive load for the connecting elements 16, etc.

According to FIG. 5 and FIG. 6, the clamping connectors 26 are for example made of two parts 26 a and 26 b being connectable by means of corrosion-resistant screws 27, said parts accommodating between them conductor section 25 on the one hand and the pertinent end of the ground conductor 17 on the other hand. Further, the one part (e.g. 26 b) may be provided with an anti-twisting element 28 in form of a web or the like which is moulded to it and which lays itself in a mounted condition against a side wall of the long-stator 1 and thus prevents undesirable twisting of the clamping connector 26.

Based upon these measures as outlined hereinabove it is achieved that the ground conductor 17 in the area of the separation points 22 is not overloaded and that the service life of the sleeves 11 in these areas is increased. Appropriate loops may also be mounted at other critical intersections between long-stator sections or ground conductor ends.

The described clamping connectors 26 support themselves according to FIG. 4 entirely through the connection between the ground conductor 17 and the conductor section 25. Therefore, they are co-carried by the ground conductor 17 and will be excited to oscillate if the ground conductor 17 oscillates. A disadvantage might turn out to be the own weight of the clamping connectors 26. Said weight may act upon the ground conductor 17 and may act as a swinging mass.

In a second embodiment of the present invention according to FIG. 7 and FIG. 8, therefore, it is provided not to cut the ground conductor 17 in the area of the separation point 22, but to form a conductor section 31 into a loop 32 which again provides a desired ground conductor reserve, said section 31 bridging the separation point 22 and being produced in a one-part configuration with and connected to said ground conductor 17. On account of the low flexibility and/or high stiffness of a stainless steel rope, it may happen that the ground conductor 17 leaps out from a plurality of connecting elements 16, with the consequence that an undesirably plurality of sleeves 11 are not grounded any longer. According to the present invention, it is therefore also provided for to connect the conductor section 31 on both sides of the separation point 22 firmly with the adjacent stator sections 1 a and 1 b. This is done in the embodiment by the aid of a clamp 33 each (see also FIG. 8) which consists of a material strip preferably made of stainless steel which has a take-up 34 destined for accommodation of the conductor section 31 and obtained by bending-over the material strip by 360° as well as two mounting sections 35 adjacent to this take-up 34. The take-up 34 can be laid around the conductor section 31 by spreading-up the mounting sections 35 and then be fastened by means of a fixing screw 36. Accordingly, the fixing screw 36 can for example be plugged through holes 37 in the mounting sections 35 and then be screwed into a threaded bore provided in the stator section 1 a, 1 b, whereby at the same time the conductor section 31 can be fixed axially unshiftably by clamping in the clamps 33. In this manner it is possible to make the loop 32 relatively short and to ensure that it is firmly connected to the stator sections 1 a, 1 b at points between which there are no more than two grooves 2 a, 2 b, as shown FIG. 7. The advantage thus achieved is that the arrangement can be so chosen that only those two sleeves 11 are not grounded which lie in the grooves 2 a, 2 b of the two stator sections 1 a, 1 b, i.e. directly adjacent to the separation point 22, because here the loop 32 leaps out from the pertinent connecting elements and/or spring channels 16 which, however, has no impact on the grounding of the overall system. In contrast therewith, the ground conductor 17 is safely held by the aid of clamps 33 in the sleeves 11 of adjacent grooves 2 c, 2 d and all further sleeves 11 so that the desired grounding is obtained here.

The prerequisite to be fulfilled in the embodiment according to FIG. 7 and FIG. 8 is that the stator sections 1 a, 1 b are provided with threaded bores for the fixing screws 36 lying near the critical separation point 22. In the third embodiment of the invention shown in FIG. 9 to FIG. 17 and currently considered the best, this is avoided by providing a mounting means 39 a, 39 b on each side of the separation point 22, said mounting means being fastened by a clamping action to a cross member 40 a, 40 b which serves for mounting the relevant stator section 1 a, 1 b to a guideway not shown here for the magnetic levitation railway. Such cross members 40 which as a rule are arranged in a dovetail-shaped groove at the upper side of stator sections 1 a, 1 b and fastened by means of screws 41 to the guideway are generally known (e.g. DE 39 28 277 C1, DE 197 03 497 A1) and therefore they need not be explained in greater detail. It is merely to be mentioned that the cross members 40 have bottom parts being designed according to the dovetail-shaped grooves and having side faces 42 (FIG. 10) that are obliquely inclined downward and outwardly.

The mounting means 39 a and 39 b are preferably of an identical design, which is the reason why only the mounting means 39 a is described in greater detail hereinafter.

In accordance with FIG. 11 to FIG. 16, the mounting means 39 a has at its upper side two pairs of first and second guiding elements 43 and 44, which stand opposite to each other at such a preselected distance (FIG. 11) that they confine a take-up space 45 between them for accommodating the lower part of the pertinent cross member 40 a (FIG. 9, 10). For this purpose, the first guiding elements 43 are arranged obliquely and/or like a roof in accordance with the side faces 42 and so shaped that they can be laid on the two side faces 42 when the mounting means 39 a is approached from a front side of the cross member 40 a, as is particularly shown in FIG. 9 and FIG. 10. Contrary, the second guiding elements 44 are so arranged and configured that they abut the undersides 46 when the mounting means 39 a is pushed onto the cross member 40 a, as becomes evident from FIG. 10. Moreover, the guiding elements 43 and 44 are preferably so arranged in relation to each other that they are resiliently spread apart with a slight pressure when pushed onto the cross member 40 a so that the mounting means 39 a when having been pushed onto the bottom part of the cross member 40 a is connected in a vertical direction, i.e. in parallel to the screws 41, mainly in a form-locking (positive) manner to the cross member 40 a, whereas it is vertically thereto, i.e. in the direction of the cross member axis, connected by clamping action, i.e. in a force-locking manner to the cross member 40 a. The same applies to the connection of the mounting means 39 b with the cross member 40 b.

As shown particularly on FIG. 11 to FIG. 17, the mounting 39 a contains an oblong, L-shaped base part 47 with a longitudinal axis 48 (FIG. 11). In the mounted state evident from FIG. 9 and FIG. 10, the base part 47 forms a rear side of mounting means 39 a and abuts the relevant stator section 1 a, with the longitudinal axis 48 being arranged in parallel to the longitudinal axis 3 (FIG. 1) of the stator section 1 a. Moreover, at the outer sides of the guiding element 43,44 remote from the take-up space 45, the mounting means 39 a has two clamping connectors 49 and 50 arranged at different levels, as is particularly shown in FIG. 11 to FIG. 16. Accordingly, the clamping connectors 49 arranged at the lower level are arranged at a greater distance measured in the direction of the longitudinal axis 48 than the two clamping connectors 50.

Each clamping connector 49 comprises a tongue 51 mounted to the base part 47 and protruding from it vertically, a counterpiece 52 opposing the tongue 51 at a certain distance, a clamping screw 53 projecting through both of them, and a nut 54 screwed onto it. In a similar manner, each clamping connector 50 comprises a tongue 55 mounted to the base part 47 and protruding from it vertically, a counterpiece 56 opposing the tongue 55 at a certain distance, a clamping screw 57 projecting through both of them, and a nut 58 screwed onto it. The heads of the clamping screws 53, 57 and the nuts 54, 58 each are supported on the outer sides of the tongues 51, 55 or counterpieces 52, 56, respectively.

In the embodiment according to FIG. 9 to FIG. 17, analogously to FIG. 7 and FIG. 8, a ground conductor 17 in combination with a separate conductor section 25 formed to a loop 24 is provided which spans over the separation point 22 like a bridge. As is particularly shown in FIG. 9 and FIG. 10, the two ends of the conductor section 25 are inserted into the two clamping connectors 50, whereupon the clamping screws 57 are screwed onto the nuts 58, thus clamping the ends of the conductor section 25 firmly between the tongues 55 and the counterpieces 56. Optionally, these ends can be fixed only in the clamping connectors 50 lying closer to the separation point 22 or in both clamping connectors 50 of the mounting means 39 a and 39 b, as indicated on FIG. 17 in an only partly representation of the clamping connectors 49. Contrary, the free ends of the ground conductor 17 are inserted in a similar manner into the clamping connectors 49 and firmly clamped by tightening the clamping screws 53 and nuts 54 between the tongues 51 and the counterpieces 52, wherein these ends are optionally fixed only in the clamping connector 49 lying remote from the separation point 22 or, as shown in FIG. 9 and FIG. 10, preferably in both clamping connectors 49 of the mounting means 39 a and 39 b. To avoid any bending of the ground conductor 17, the mounting means 39 a, 39 b are expediently so configured that those parts of the tongues 51 and counterpieces 52, between which the ground conductor 17 is clamped, are arranged flush with the connecting elements 16 of the sleeves 11 when being in a mounted state.

Besides, like in the embodiment according to FIG. 4 to FIG. 6, this embodiment yields the advantage that the free ends of the ground conductor 17 and/or the security means 23 mounted to them can be laid very closely to the separation point 22, as is particularly shown in FIG. 9, and therefore, the sleeves 11 which are arranged in the two grooves 2 a and 2 b lying immediately next to the separation point 22 can be well grounded. In difference to FIG. 7, there is no danger that the free ends of the ground conductor 17 leap out from the connecting elements 16 of these sleeves 11.

In accordance with a fourth embodiment shown on FIG. 18, the mounting means 39 a, 39 b evident from FIG. 9 to FIG. 17, are applied to a continuous ground conductor 17 analogously to FIG. 7 by providing the latter with conductor section 31 bridging the critical separation point 22 and being formed to a loop 32. For this purpose, the two mounting means 39 a, 39 b according to FIG. 18 are pushed on both sides of the separation point 22 onto one cross members 40 a, 40 b provided there until they abut the relevant stator sections 1 a, 1 b. Subsequently, the ground conductor 17 is inserted for example into the clamping connectors 49 under formation of a loop 32 with the clamping screws 53 having been loosened, and then firmly clamped between the tongues 51 and counterpieces 52 by tightening the clamping screws 53 and/or nuts 54. In this case, the clamping connector 49 lying closer to the separation point 22 replaces the clamp 33 shown in FIG. 7 and FIG. 8, because by means of these clamping connectors 49 it is ensured that the ground conductor 17 despite the formation of a loop 32, safely remains in those sleeves 11 that are arranged in the grooves 2 c, 2 d following next, as is clearly shown on FIG. 18.

The embodiments described by way of FIG. 9 to FIG. 18 bear the advantage that the mounting means 39 a, 39 b cause on the one hand the clamping of the ground conductor 17 and/or conductor sections 25, 31 and on the other hand the fastening thereof to the stator sections 1 a, 1 b. It is thereby avoided that the mounting means 39, 39 b transfer additional vibrations, oscillations or the like to these lines and impede their desired grounding function. In particular, as opposed to FIG. 4 to FIG. 6, the deadweight of the mounting means 39 a, 39 b cannot transfer any forces onto the ground conductor 17 and/or the conductor sections 25, 31. Finally, the embodiment examples of FIG. 4 to FIG. 6 and FIG. 9 to FIG. 17 also yield the advantage that the conductor sections 25, 31 providing the line reserves can be firmly connected with the clamping connectors 26 or 50, respectively already at manufacturer's works so that at the construction site it will only be necessary to establish the connections for the ground conductor 17.

The described clamping connectors 26 and mounting means 39 a, 39 b as well as the pertinent component parts are preferably made of the same material as the ground conductor 17 and the conductor sections 25 and 31, i.e. for example from stainless steel, in order to preclude any contact corrosion as outlined hereinabove. In accordance with an embodiment currently considered the best, the holders 39 a and 39 b are produced as follows (see FIG. 19 to FIG. 27):

To begin with, an e.g. approximately 2 mm thick metal sheet preferably made of stainless steel is cut in the manner shown in FIG. 19 by laser cutting, punching or in any other form. In a middle area, the cut plate blank 61 comprises the base part 47 (see FIG. 11 to FIG. 16), from which two sheet flaps 62 and 63 protude mainly vertically towards one side and another two sheet flaps 64, 65 towards the opposite side. The flaps 62, 63 serve for producing the clamping connectors 49, comprise the tongues 51 and the counterpieces 52 according to FIG. 15 and FIG. 16, and are therefore, mainly mounted at the ends of the base part 47. Contrary, flaps 62, 64 serve for producing the clamping connectors 50, comprise the tongues 55 and the counterpieces 56 and are mounted, therefore, as viewed in the direction of the longitudinal axis 48 (FIG. 11), between the flaps 62, 63.

The base part 47 and the flaps rags 62 to 65 comprise a plurality of bending lines which are shown as dash-dotted lines in FIG. 18 and which are designated, for example, with the reference numerals 66 to 74. Since the sheet blank 61 is preferably configured in mirror-symmetrical arrangement with reference to a central plane indicated by a line 75, flaps 63 and 65 have bending lines not designated specifically that correspond to the bending lines 66 to 74. The bending lines 66 to 74 can be imaginary lines, but also preselected nominal bending lines that are defined by grooves or the like in the flaps 62 to 65.

To produce the mounting means 39 a, the metal sheet 61 is for example initially bent by 90° around the bending line 66 in order to establish the L-shape of the base part 47. Moreover, the flap 62 is bent by approximately 90° around each bending line 67, 68 (towards the top as shown on FIG. 19), while the flap 64 is bent by approximately 90° (also towards the top as shown on FIG. 19) around the bending line 70. The flaps 63, 65 are bent in a similar manner. Finally, the guiding elements 43 and 44 connected to the flaps 64 and 65 are bent around the bending lines 72 to 74 in the manner required for assembly shown in FIG. 9 and FIG. 10, thus obtaining a shape for the mounting means 39 a as shown on FIG. 20. The mounting means 39 b is produced in a similar manner.

The mounting means 39 a, 39 b can be stored, transported and taken to the construction site in the described pre-shaped form of FIG. 20. There, depending on the type of application, the ends of the ground conductor 17 and/or conductor section 25, 31 are inserted and the counterpieces 52, 56 are bent, for example manually, around the bending lines 69, 71 towards the inside, the clamping screws 53, 57 are introduced and the tongues 51, 55 as well as counterpieces 52, 56 are clamped against each other after the nuts 54, 58 have been turned-on. To facilitate the manual bending process, the pertinent parts of the metal sheet 61 are provided at least in the area of the bending lines 69, 71 with oblong-shaped recesses 76 and/or 77 which extend over a large part of the width of the flaps 62, 64 and/or 63, 65.

On account of this design of the flaps 62 to 65, it is possible that the counterpieces 52, 56 break-off when initially or, possibly, frequently bent or when the clamping screws 53, 57 are tightened. As a consequence hereof, the counterpieces 52, 56 might possibly slip off from the support surfaces when the clamping screws 53, 57 are finally tightened, because said support surfaces are formed by narrow webs 78, 79 (see FIGS. 19 and 20) existing at the ends of the tongues 51, 55, being arranged between the bending lines 68, 69 and/or 70, 71, and protruding primarily vertically to the other portions of the flaps 51 and/or 55. This would result in that the ground conductors 17 and conductor sections 25, 31 could not be clamped sufficiently between the tongues 51, 55 and the counterpieces 52, 56 when the clamping screws 53, 57 are tightened. To avoid this, the bending lines 69, 71 and recesses 76, 77 are so configured that nominal breaking lines are formed and that the counterpieces 52, 56 can be separated easily from the webs 78, 79 by bending them to and fro. Then the shape of mounting means 39 a and/or 39 b is obtained as shown on FIG. 21.

The counterpieces 52, 56 obtained by means of the nominal breaking lines are illustrated in FIG. 22 to FIG. 27. Because of the chosen shape of the recesses 76 and 77, they have short projections 80 or 81, respectively (FIG. 22, 24), at the ends of the breaking lines, and corresponding projections 83, 84 remain standing at the webs 78, 79 as shown in FIG. 21.

When producing the cut sheet blank 61 (FIG. 19), the free front edges 84, 85 of the counterpieces 52 and 56 are provided at both their ends with a recess 86 or 87, respectively which is also shown in FIG. 22 to FIG. 27 and the size of which mainly corresponds to the size of the projection 83 and 84 in FIG. 21. This serves the purpose of laying the separated counterpieces 52, 53 after a rotation by 180° as shown in FIG. 26 and FIG. 27 onto the webs 78, 79 (FIG. 21) in such a manner that sections of the end edges 84 and 85 remaining between the recesses 86 and 87 come to rest on the free end edges of the webs 78 and/or 79, and that the projections 84, 85 are taken-up by assigned recesses 87 and 88, thus obtaining a defined support for the end edges 84, 85 on the webs 78, 79. Moreover, the length of the counterpieces 52, 56 is so chosen that the projections 80 and 81 support themselves at the base part 47 in this status as indicated on FIG. 10 and FIG. 18, and then act as spacers so that the defined support of the end edges 84, 85 of the counterpieces 52, 56 on the relevant webs 78, 79 is maintained even after the ground conductor 17 and/or the conductor section 25, 31 have been inserted and fixed.

In this variant, as shown for example by the enlarged representations in FIGS. 10, 17, and 18, the ground conductor 17 and/or conductor sections 25, 31 are inserted between the tongues 51, 55 and counterpieces 52, 56 at places which are located between the base part 47 and the clamping screws 53, 57, i.e. at the sides of the clamping screws 53, 57 which are remote from the support points on webs 78, 79. As a consequence hereof, no undesirable lever action is exerted on the counterpieces 52, 56 when the clamping screws 53, 57 are tightened and a safe and firm clamping of the ground conductor 17 as well as the conductor sections 25, 31 is thus ensured.

An essential advantage of those measures described and shown in FIG. 21 to FIG. 27 lies in the fact that the mounting means 39 a, 39 b can be completely prefabricated. For this purpose, it is also advantageous to fix the nuts 54, 58 after the bending process according to FIGS. 20 and/or 21 on the tongues 51, 55 by welding or the like and to loosely screw the clamping screws 53, 57 into them. On the construction site, it will then only be required to push the mounting means 39 a, 39 b, composed to a one-part construction unit, onto the cross members 40 a, 40 b and then to firmly clamp the ground conductor 17 and/or conductor sections 25, 31 by loosening and/or tightening the four clamping screws 53, 57.

As is particularly shown in FIGS. 24, 25, and 27, each counterpiece 56 is provided with the second guiding element 44 (see also FIG. 17). If the counterpiece 56 is so designed at the sheet blank 1 in conformity with the description given hereinabove that it is separated during the bending process in order to turn it around by 180° afterwards in the described manner, this must be duly considered by an appropriate pre-bending of the second guiding elements 44. Therefore, FIG. 20 shows that the second guiding elements 44 each are so pre-bent and mounted to the counterpiece 56 that they obtain their correct position only if the counterpiece 56 is indeed separated from the web 79 of the tongue 55, turned around by 180° and then laid onto the web 79 in the correct arrangement.

The embodiment described by way of FIG. 19 to FIG. 27 bears the advantage that the mounting means 39 a, 39 b can be obtained by simple bending devices from the one-piece plate 61. Both a low-cost production and a low-cost assembly are thereby achieved, with the latter requiring no preparatory work on stator sections 1 a, 1 b and cross members 40 a, 40 b.

The present invention is not limited to the embodiments described herein that can be varied in a plurality of ways. For example, the sleeves 11 could be of a two-piece or multiple-piece configuration and be connected on each side of the long stator 1 to one ground conductor 17 each, in the case of which the described formation of a loop should be provided on both sides of every critical separation point 22. Furthermore, the mounting means 39 a, 39 b described by way of FIG. 10 to FIG. 27 can be varied in a multitude of ways, particularly with regard to their shapes and sizes as well as with regard to the attachment and configuration of the guiding elements 43 and 44. Moreover, it would be possible to provide simple riveted connections instead of the described clamping screws or to provide every tongue 51, 55 or every counterpiece 52, 56 with an appropriate threaded bore instead of the nuts 54, 58. It is also self-evident that the relative position of the various parts in relation to each other as well as the length of the mounting means 39 a, 39 b should be chosen with due consideration of the positions of the cross members 40. If there are no cross members 40 or if they are not available for fixing the mounting means 39 a, 39 b, the latter could naturally also be fastened like the clamps 33 with screws or the like to the stator sections 1 a, 1 b. It is also possible to apply other ground conductors 17 and conductor sections 25 and/or 31. Furthermore, the invention also relates to a magnetic levitation railway equipped with the described long-stator. Finally it is self-explanatory that the different features can also be applied in combinations other than those described and shown hereinabove. 

1. A long-stator for a magnetic levitation railway, comprising: a plurality of stator sections (1 a, 1 b) that are arranged one behind the other and adjoin one another at separation points (22), said sections having grooves (2) and teeth following each other in a longitudinal direction, at least one alternating current winding (4) laid into said grooves (2) and at least one ground conductor (17) extending in longitudinal direction for grounding said alternating current winding (4), characterized in that the ground conductor (17) comprises, at least in the vicinity of critical separation points (22), a conductor section (25, 31) that bridges the separation point (22) and is configured as a loop (24, 32).
 2. A long-stator according to claim 1, characterized in that the conductor section (31) is configured in a continuous part of the ground conductor (17) and firmly connected with the adjacent stator sections (1 a, 1 b) on both sides of the critical separation points (22).
 3. A long-stator according to claim 2, characterized in that the loop (32) is fastened at those points to the stator sections (1 a, 1 b) adjacent to the separation point (22), in between of which there are no more than two grooves (2 a, 2 b).
 4. A long-stator according to claim 2, characterized in that the conductor section (31) is fastened with one clamp (33) each to the relevant stator section (1 a, 1 b).
 5. A long-stator according to claim 2, characterized in that the conductor section (31) is fastened to the relevant stator section (1 a, 1 b) on each side of the critical separation points (22) with at least one clamping connector (49).
 6. A long-stator according to claim 1, characterized in that the ground conductor (17) is interrupted in the region of the critical separation points (22) under formation of two free ends and that the conductor section (25) connects the two free ends electrically to each other.
 7. A long-stator according to claim 6, characterized in that the two free ends of the ground conductor (17) are provided with security means (23) to prevent them from splicing.
 8. A long-stator according to claim 6, characterized in that the conductor section (25) is fastened by loose clamping connectors (26) to the two free ends of the ground conductor (17).
 9. A long-stator according to claim 8, characterized in that the clamping connectors (26) are made of stainless steel.
 10. A long-stator according to claim 8, characterized in that the clamping connectors (26) are provided with anti-twisting elements (28) or configured as such elements.
 11. A long-stator according to claim 6, characterized in that the conductor section (25) is connected to the two free ends of the ground conductor (17) by means of mounting means (39 a, 39 b) fastened to the relevant stator sections (1 a, 1 b).
 12. A long-stator according to claim 11, characterized in that the stator sections (1 a, 1 b) are provided with cross members (40 a, 40 b) destined for fastening to a guideway of a magnetic levitation railway and that the mounting means (39 a, 39 b) comprise two guiding elements (43, 44) each destined for being pushed onto one of the cross members (40 a, 40 b) and opposing each other with a preselected distance.
 13. A long-stator according to claim 11, characterized in that each mounting means (39 a, 39 b) comprises two pairs of clamping connectors (49, 50) for the free ends of the ground conductor (17) and the conductor section (25).
 14. A long-stator according to claim 13, characterized in that the clamping connectors (49, 50) each comprise a tongue (51, 55) attached to the mounting means (39 a, 39 b) and a counterpiece (52, 56).
 15. A long-stator according to claim 11, characterized in that the mounting means (39 a, 39 b) are made of a cut sheet blank (61) produced as one piece.
 16. A long-stator according to claim 14, characterized in that the counterpiece (52, 56) is a separate part obtained by separation from the sheet blank (61).
 17. A long-stator according to claim 11, characterized in that the mounting means (39 a, 39 b) are made of stainless steel.
 18. A long-stator according to claim 14, characterized in that the tongues (51, 55) and counterpieces (52, 56) are projected by a clamping screw (53, 57).
 19. A long-stator according to claim 18, characterized in that nuts (54, 58) fastened to the tongues (51, 55) or counterpieces (52, 56) are assigned to the clamping screws (53, 57).
 20. A long-stator according to claim 11, characterized in that each mounting means (39 a, 39 b) is a completely prefabricated component part.
 21. A magnetic levitation railway having of a long-stator as part of a long-stator linear motor, wherein said long-stator comprises grooves (2) and an alternating current winding (4) inserted into said grooves (2), said winding having a sheath (21) which is at least partly electrically conductive and wherein a ground conductor (17) is laid in the longitudinal direction of said long-stator, characterized in that the ground conductor (17) comprises, at least in the vicinity of a critical separation point (22) between two stator sections (1 a, 1 b), a loop (24, 32) that bridges the separation point (22) according to claim
 1. 